SignalMap

DePIN Cellular Coverage Intelligence Network

SignalMap turns smartphones into cellular signal measurement nodes. Contributors earn FLOW token rewards for mapping real-world network coverage — data that telecom operators and IoT companies pay millions within Drive Testing budgets to collect.

Architecture

┌─────────────────┐     ┌──────────────┐     ┌──────────────────┐
│  Mobile App     │────▶│  Backend API │────▶│  Flow EVM        │
│  (React Native) │     │  (Express)   │     │  (Trust Receipts)│
│                 │     │              │     │  ERC-8004        │
│  Native Android │     │  Supabase    │     └──────────────────┘
│  Sensor Module  │     │  IPFS/Pinata │
└─────────────────┘     └──────────────┘

What Data We Collect

Each reading captures hardware-sourced RF data via a custom Android native module (CellularInfoModule.kt):

Data Point	Source	Value
Signal Strength	TelephonyManager	dBm (e.g. -85)
Carrier	TelephonyManager	China Mobile, T-Mobile, etc.
Network Generation	TelephonyManager	3G / LTE / 5G
GPS Coordinates	expo-location	lat/lng
Wi-Fi Density	NetInfo	nearby AP count

Data is not spoofable — it comes directly from the device's radio chipset, not from any API.

On-Chain Verification

Every validated reading is minted as an ERC-8004 Trust Receipt on Flow EVM Testnet:

• TrustReceipts: 0x3AFC288E6b7bD6c69dBa622EE57659f450BC1D61
• ChallengeManager: 0xA3E1f07aED2d1120FABF75dd0B8a6a5523fcAd25
• Chain: Flow EVM Testnet (Chain ID: 545)

Tech Stack

• Mobile: React Native (Expo) + Custom Kotlin Native Modules
• Backend: Node.js / Express
• Database: Supabase (PostgreSQL)
• Storage: IPFS via Pinata
• Blockchain: Flow EVM (Solidity contracts)
• State: Zustand + AsyncStorage (persistent)

Project Structure

├── src/
│   ├── screens/          # App screens (Map, Login, Profile)
│   ├── services/
│   │   ├── api.ts        # Backend API client with safety catch failover
│   │   └── signalCollector.ts  # Signal data collection orchestrator
│   └── store/
│       └── useMapperStore.ts   # Persistent state (Zustand + AsyncStorage)
├── android/
│   └── app/src/main/java/com/knayx/signalmap/
│       ├── CellularInfoModule.kt   # Native bridge: TelephonyManager → JS
│       └── CellularInfoPackage.kt  # RN package registration
├── server/
│   ├── index.js          # Express API server
│   ├── auth.js           # Authentication routes
│   └── supabaseClient.js # Database client
└── railway.json          # Deployment config

Setup

# Install dependencies
npm install
cd server && npm install && cd ..

# Copy env template and fill in your keys
cp .env.example .env

# Run mobile app + backend concurrently
npm run dev:all

License

MIT